BSP threads (British Standard Pipe)

- BSPP (British Standard Pipe Parallel) - G (male) and Rp (female): 
This is a cylindrical thread type. Sealing is typically achieved by a pre-installed seal on the fitting. It is only compatible with a thread of the same type.

- BSPT (British Standard Pipe Tapered) - R (male) and Rc (female): 
This is a tapered thread type. Sealing is typically achieved by a pre-coating in the thread.

NPT & NPTF threads (National Pipe Threads):

- NPT Thread (National Pipe Thread): 
This is a standard American tapered thread type. Sealing is typically achieved by a pre-coating in the thread. It is only compatible with a thread of the same type.

_ NPTF (National Pipe Thread Fuel):

It is a standard American tapered thread type. Sealing is achieved through the irregular shapes of the threads, rather than a pre-coating in the thread. It is only compatible with a thread of the same type.

Metric threads:

It is a standard ISO cylindrical thread type.

Sealing is typically achieved by a pre-installed seal on the fitting or a sealing washer.

It is only compatible with a thread of the same type.